LI-JUNE MING
Department of Chemistry and Institute for Biomolecular Science University of South Florida Tampa, Florida 33620-5250

Abstract: Paramagnetic lanthanide(III) ions (Ln3+)
have been used successfully as spectroscopic probes for the study of chemical,
physical and physiological properties of many Ca2+-dependent
biological systems in the past several years. Some paramagnetic Ln3+
(e.g. Pr3+, Eu3+,
and Yb3+) possessing very short electronic
relaxation times are able to exhibit relatively sharp isotropically shifted
1H NMR features attributable to the protons
in the close proximity of the metal. Thus, the use of such Ln3+
ions as substitutes for Ca2+
in proteins raises the possibility of detailed NMR study of the Ca2+
binding environment in proteins. These paramagnetic Ln3+ ions have
also been used as NMR probes for the study of the structural and functional
roles of several metal-dependent antibiotics, such as the anthracyclines.
We report in this contribution the use of two dimensional NMR techniques
for the studies of paramagnetic Ln3+-substituted
Ca2+ proteins in terms of the configuration
of the metal-binding sites and the interactions with ligands, and for the
study of metallo-antibiotics.